/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.dubbo.config.spring.util;

import org.springframework.core.env.AbstractEnvironment;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.EnumerablePropertySource;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import org.springframework.core.env.PropertySources;

import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Properties;


/**
 * {@link PropertySources} Utilities
 * <p>
 * The source code is cloned from https://github.com/alibaba/spring-context-support/blob/1.0.2/src/main/java/com/alibaba/spring/util/PropertySourcesUtils.java
 *
 * @since 2.6.6
 */
public abstract class PropertySourcesUtils {

  /**
   * Get Sub {@link Properties}
   *
   * @param propertySources {@link PropertySource} Iterable
   * @param prefix the prefix of property name
   * @return Map
   * @see Properties
   */
  public static Map<String, Object> getSubProperties(Iterable<PropertySource<?>> propertySources,
      String prefix) {

    // Non-Extension AbstractEnvironment
    AbstractEnvironment environment = new AbstractEnvironment() {
    };

    MutablePropertySources mutablePropertySources = environment.getPropertySources();

    for (PropertySource<?> source : propertySources) {
      mutablePropertySources.addLast(source);
    }

    return getSubProperties(environment, prefix);

  }

  /**
   * Get Sub {@link Properties}
   *
   * @param environment {@link ConfigurableEnvironment}
   * @param prefix the prefix of property name
   * @return Map
   * @see Properties
   */
  public static Map<String, Object> getSubProperties(ConfigurableEnvironment environment,
      String prefix) {

    Map<String, Object> subProperties = new LinkedHashMap<String, Object>();

    MutablePropertySources propertySources = environment.getPropertySources();

    String normalizedPrefix = normalizePrefix(prefix);

    for (PropertySource<?> source : propertySources) {
      if (source instanceof EnumerablePropertySource) {
        for (String name : ((EnumerablePropertySource<?>) source).getPropertyNames()) {
          if (!subProperties.containsKey(name) && name.startsWith(normalizedPrefix)) {
            String subName = name.substring(normalizedPrefix.length());
            if (!subProperties.containsKey(subName)) { // take first one
              Object value = source.getProperty(name);
              if (value instanceof String) {
                // Resolve placeholder
                value = environment.resolvePlaceholders((String) value);
              }
              subProperties.put(subName, value);
            }
          }
        }
      }
    }

    return Collections.unmodifiableMap(subProperties);

  }

  /**
   * Normalize the prefix
   *
   * @param prefix the prefix
   * @return the prefix
   */
  public static String normalizePrefix(String prefix) {
    return prefix.endsWith(".") ? prefix : prefix + ".";
  }
}
